Re: [PATCH v2 16/18] arm64: dts: hi3660: Harmonize DWC USB3 DT nodes name

[John Stultz]

On Wed, Nov 11, 2020 at 1:22 AM Serge Semin
<Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> In accordance with the DWC USB3 bindings the corresponding node
> name is suppose to comply with the Generic USB HCD DT schema, which
> requires the USB nodes to have the name acceptable by the regexp:
> "^usb(@.*)?" . Make sure the "snps,dwc3"-compatible nodes are correctly
> named.
>
> Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> Acked-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/hisilicon/hi3660.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> index d25aac5e0bf8..aea3800029b5 100644
> --- a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> +++ b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> @@ -1166,7 +1166,7 @@ usb_phy: usb-phy {
>                         };
>                 };
>
> -               dwc3: dwc3@ff100000 {
> +               dwc3: usb@ff100000 {
>                         compatible = "snps,dwc3";
>                         reg = <0x0 0xff100000 0x0 0x100000>;


Oof. So this patch is breaking the usb gadget functionality on HiKey960 w/ AOSP.

In order to choose the right controller for gadget mode with AOSP, one
sets the "sys.usb.controller" property, which until now for HiKey960
has been "ff100000.dwc3".
After this patch, the controller isn't found and we would have to
change userland to use "ff100000.usb", which would then break booting
on older kernels (testing various LTS releases on AOSP is one of the
key uses of the HiKey960).

So while I understand the desire to unify the schema, as HiKey960
really isn't likely to be used outside of AOSP, I wonder if reverting
this one change is in the best interest of not breaking existing
userland?

thanks
-john